NemaStudio now supports the NMEA 0183 TAG Block

Introduction

From version 1.32 NemaStudio supports the TAG block as defined in NMEA 0183 Version 4.0.

NMEA’s definition of the TAG Block

The NMEA defines the function of the TAG Block as follows:

“The TAG Block structure and content is intended to clarify the relationship of sentences to each other and to the equipment between which sentences are communicated. The TAG Block structure introduces the addition of sentence related information into the character stream containing NMEA 0183 defined sentences.”

The TAG Block format

Basically a TAG Block contains one or more parameters. A parameter has a parameter code and a parameter value. Parameter example: “-s:GP0003”. Currently a maximum of 7 different parameters are defined (See below).

A TAG Block always starts and ends with a backslash (“\”” and includes a checksum preceded by an asterisk (“*”).   The TAG Block always precedes the NMEA 0183 sentence. Example TAG Block (red) preceding HDT sentence:

\s:HE0002,c:1474107266,n:5*20\$HEHDT,119.9,T*2F

TAG Block parameters

Currently the TAG Block can contain one or more of the following parameters:

Parameter code	Parameter name	NemaStudio support
-c	UNIX time	yes
-d	Destination Id	no
-g	Grouping	no
-n	Line count	yes
-r	Relative time	no
-s	Source Id	yes
-t	Text string	no

 

As can be seen from the table NemaStudio V.1.32 supports   the following TAG Block parameters: –c, –n and –s. Depending demand Sailsoft may include more parameters in future versions of NemaStudio.

The TAG Block is optional

Using the TAG Block is optional and can be set in the NMEA settings tab of the General Settings. This ensures compatibility with applications that do not support the TAG Block. The TAG Block and the parameters can be selected individually in NemaStudio. If the checkbox “Send TAG Block” is unchecked the parameter checkboxes are disabled.

Examples with TAG Block and Multicast UDP from NemaStudio

UdPbC?\s:VE0001*07\$VWVHW,135.0,T,155.0,M,18.0,N,33.3,K*58
UdPbC?\s:SO0001*08\$SDDBT,32.8,f,10.0,M,05.5,F*3E
UdPbC?\s:GP0001*03\$GPZDA,112250.80,17,09,2016,2,0*63
UdPbC?\s:AI0009*14\!AIVDM,1,1,,A,494q>JQv2HcFkOrLopM30u10050l,0*04

(Note: the question mark after the UdPbC string represents the null terminator.)